1. Field of the Invention
The invention generally relates to handling of an Equivalent Public Land Mobile Network (PLMN) list, and more particularly, to apparatuses and methods for handling the Equivalent PLMN List obtained with an attachment for emergency bearer services.
2. Description of the Related Art
In a typical mobile communication environment, a user equipment (UE), including a mobile telephone (also known as a cellular or cell phone), a laptop computer with wireless communications capability, or a personal digital assistant (PDA) etc., may communicate voice and/or data signals with one or more service network. The wireless communications between the UE and the service networks may be performed using various wireless technologies, such as the Global System for Mobile communications (GSM) technology, General Packet Radio Service (GPRS) technology, Enhanced Data rates for Global Evolution (EDGE) technology, Wideband Code Division Multiple Access (WCDMA) technology, Code Division Multiple Access 2000 (CDMA-2000) technology, Time Division-Synchronous Code Division Multiple Access (TD-SCDMA) technology, Worldwide Interoperability for Microwave Access (WiMAX) technology, Long Term Evolution (LTE) technology, LTE-Advanced technology, and others.
Take the WCDMA or LTE technology in compliance with the 3GPP TS 24.008 specification, v9.3.0 (referred to herein as the TS 24.008 specification) and the 3GPP TS 24.301 specification, v9.3.0 (referred to herein as the TS 24.301 specification), and the 3GPP TS 23.122 specification, v9.3.0 (referred to herein as the TS 23.122 specification) as an example. When a UE performs an attachment procedure or a routing area update procedure, it may receive a list of equivalent Public Land Mobile Networks (PLMNs) (or referred to as an Equivalent PLMN List) in an ATTACH ACCEPT message or a ROUTING AREA UPDATE ACCEPT message. Each entry of the list contains a PLMN code which comprises a Mobile Country Code (MCC) and a Mobile Network Code (MNC) for identifying a specific PLMN, and the UE should treat the PLMNs in the list equivalent to each other for the purposes of PLMN selection procedures, cell selection/reselection procedures, and/or handover procedures. Also, the UE keeps a list of forbidden PLMNs (or referred to as a Forbidden PLMN List) that have rejected the registration requests from the UE, i.e., the UE is forbidden to access the PLMNs in the list for normal services. With the Forbidden PLMN List, the UE may avoid selecting the forbidden PLMNs for the purposes of PLMN selection procedures, cell selection/reselection procedures, and/or handover procedures.